The present invention relates to therapeutic and prophylactic devices, and more particularly to devices for applying compressive pressures against a patient's limb.
It is known that the velocity of blood flow in a patient's extremities, particularly the legs, markedly decreases during confinement of the patient. Such pooling or stasis of blood is particularly pronounced during surgery, immediately after surgery, and when the patient has been confined to bed for extended periods of time. It is also known that stasis of blood is a significant cause leading to the formation of thrombi in the patient's extremities, which may have a severe deleterious effect on the patient, including death. Additionally, in certain patients it is desirable to move fluid out of interstitial spaces in extremity tissues, in order to reduce swelling associated with edema in the extremities.
Devices have been disclosed in U.S. Pat. Nos. 4,013,069 and 4,030,488, incorporated herein by reference, which develop and apply the desired compressive pressures against the patient's limbs. Such devices comprise a pair of sleeves which envelope the patient's limbs, and a controller for supplying fluid pressure to the sleeves. It has been found that the sleeves are relatively difficult to apply about the patient's legs due to the contour of the patient's legs. Further it has been found that the sleeves tend to bind the extremities in the region of the patient's knees, and deter flexation of the patient's knees during the extended periods of time while the sleeves are worn.